The discovery of specific benzodiazepine binding sites on receptors in the brain has initiated a search for a possible "endogenous ligand" for the receptor sites.
Compounds found to bind to the benzodiazepine receptor sites include N.sup.6 -benzyladenosine, .beta.-carbolines, zopiclone, nicotinamide, CL-218,872 (Lederle) and diazepam.
In the search for structural similarities between all of the benzodiazepine-receptor agonists and/or antagonists, a molecular overlap pattern has been developed and reported by P. Skolnick and S. Paul in Medicinal Research Reviews, 1, 3 (1981). The essential stereochemical parameters of the pattern are characteristic of compound structures such as imidazopyridines, azaindoles, pyrazolo[1,5-a]pyrimidines, and structure types corresponding to the compounds recited above.
There is continuing interest in the development of novel compounds which bind to the specific benzodiazepine binding sites, and which consequentially exhibit useful therapeutic activities.
Accordingly, it is an object of this invention to provide novel compounds which can function as endogenous ligands for benzodiazepine binding sites in the brain.
It is another object of this invention to provide novel compounds which exhibit anxiolytic, anticonvulsant and muscle relaxant effects in warm blooded animals.
It is a further object of this invention to provide chemical intermediates for the synthesis of 2-arylpyrazolo-[1,5-a]pyrimidine-3-acetic acid derivatives.
Other objects and advantages of the present invention shall become apparent from the accompanying description and examples.